My invention relates generally to lighting devices and more particularly to an electric lamp assembly suitable for use as a vehicular headlamp, among other applications. Still more particularly, my invention pertains to such a lamp assembly featuring provisions for the ready mounting and dismounting of a light bulb to and from a lamp housing.
Of a variety of devices heretofore suggested and used for detachably mounting a light bulb to a lamp housing, that which is closest and most pertinent to my invention is, as far as I know, the one described and claimed in Japanese Patent Application No. 61-225315. It teaches the provision of a flange on the base of a light bulb, and of a mounting ring for securing the light bulb to a lamp housing via the flange. The light bulb is first inserted in the lamp housing through a mounting tube coaxially extending rearwardly therefrom, until the flange butts against the extremity of the mounting tube. Then the mounting ring is attached to the mounting tube thereby capturing the light bulb flange between itself and the mounting tube. The light bulb is dismountable from the lamp housing as the mounting ring is first detached from the mounting tube.
I object to this prior art device because it necessitates the handling of the mounting ring each time the light bulb is mounted to, or dismounted from, the lamp housing. The operator must manipulate the mounting ring with one hand while grasping the light bulb with the other in order to hold the light bulb flange seated against the end of the mounting tube. This necessity for the use of both hands becomes a particular inconvenience when the lamp assembly is employed as a vehicle headlight. Vehicular headlight compartments in general have no large extra space behind the headlight assembly for accommodating both hands of a serviceman. Consequently, the change of used light bulbs with new ones has heretofore been a troublesome and time-consuming procedure.
There is another reason why I object to the noted prior art device. The mounting ring must be thoroughly removed from the lamp housing for the dismounting of the light bulb from the lamp assembly. Once removed from the lamp housing, the mounting ring may be lost if the serviceman somehow diverts his attention from the mounting ring before reinstalling it.